Selectively replicating viral vectors

Abstract

The present invention provides recombinant viruses which replicate the viral genome selectively in response to the intracellular conditions of the target cell through the use a pathway-responsive promoter which substantially inhibits viral replication in the host cell based on the phenotypic or genotypic of the infected cell. In the target cell, the promoter element of the pathway-responsive promoter is inactive and thus the virus is permitted to replicate. This results in: (1) killing the cells by natural lytic nature of the virus, and/or (2) provides a therapeutic dose of a transgene product (amplified in comparison to replication incompetent vectors) to the target cell, and (3) producing a localized concentration of the virus facilitating the infection of surrounding cells to the recombinant virus. The invention further provides therapeutic and diagnostic methods of use of the vectors, pharmaceutical formulations comprising the vectors, methods of making the vectors and transformed cells comprising the vectors.

We claim: 
     
       1. A method of making a selectively replicating vector, said method comprising:
 (a) infecting a producer cell with a recombinant virus comprising a p53 pathway-responsive promoter driving expression of an inhibitor of viral replication, wherein the promoter is activated by the presence of functional p53 and the inhibitor of viral replication is an E2F-RB fusion protein; 
 (b) culturing said infected producer cell under conditions so as to permit replication of the viral genome in the producer cell, 
 (c) harvesting and lysing the producer cell, and 
 (d) purifying the recombinant virus, 
 thereby making the selectively replicating vector. 
 
     
     
       2. The method of  claim 1  wherein the producer cell is selected from a 293 cell and a A549 cell. 
     
     
       3. The method of  claim 1  wherein purification of the virus is achieved by column chromatography. 
     
     
       4. The method of  claim 1 , wherein the recombinant virus is derived from the genus adenoviridae.